KR19980075346A - LCD Unit for High Brightness Single-Phase LCD Projectors - Google Patents

Abstract

The present invention relates to an LCD device for a high-brightness liquid crystal projector, comprising: a microlens installed such that a straight line connecting the center of the microlens from the center of the LCD cell is inclined by a predetermined angle with respect to the horizontal cross section of the LCD, and the horizontal cross section of the LCD. To provide an LCD device for a high brightness single-ended liquid crystal projector comprising a light ray providing means for providing R, G, B light at the same angle as a straight line connecting the center of the micro lens at the center of the LCD cell, By making the angle of the light beam to the angle that can take full advantage of the characteristics of the contrast ratio of the LCD, it is possible to obtain an effect of greatly improving the contrast ratio of the LCD.

Description

LCD Unit for High Brightness Single-Phase LCD Projectors

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an LCD device used in a single plate type liquid crystal projector, and more particularly, to an LCD device capable of improving contrast.

In general, the CRT is mainly used as a projector for projecting an image displayed on a CRT onto a screen, but when applied to a large screen, a problem arises that the volume becomes large and takes up a large area during installation. Projectors using display elements have been developed.

In the projector using the liquid crystal display device, since the liquid crystal display device does not emit light by itself, a separate light source is required, and the brightness of the screen and the sharpness of color are determined according to the light source.

1 is a view showing the configuration of a general liquid crystal projection apparatus.

Referring to FIG. 1, reference numeral 50 denotes a light source, 51 denotes a parabolic reflector reflecting light emitted from the light source 50 to travel in one direction, and 52 denotes a light source 50 emitted from the light source 50. A UV / IR filter for blocking unwanted beams, i.e. ultraviolet and infrared rays, in the beam, 53 represents a condensing lens for collecting the beam exiting the UV / IR filter 52, and 54 a surface The liquid crystal panel with the three primary color filters in the mosaic state is shown.

Reference numerals 55 and 56 denote polarizing plates arranged before and after the liquid crystal panel 50, and reference numeral 57 denotes a projection lens.

As shown in FIG. 2, the color filter used in the liquid crystal panel 54 includes pixels having a stripe structure or a delta structure.

The liquid crystal projection apparatus having the above configuration has the advantage of being simple and compact in construction, but two-thirds of the beams irradiated onto the liquid crystal panel 54 are absorbed by the color filter as shown in FIG. 2. do. For example, in a pixel to display R, an R filter is attached so that G and B are absorbed and removed. Accordingly, only one third of the beams incident on the liquid crystal panel 50 can be used, which causes a problem in that the brightness of a light beam theoretically provided falls below one third.

Due to the above problems, a technique has been studied to improve brightness without using a color filter by injecting a light beam having a wavelength required for display into a liquid crystal panel at different angles and synthesizing it on a screen to obtain a color screen.

3 is a view showing the configuration of an optical system for a liquid crystal display device which does not use a color filter according to the prior art.

Referring to FIG. 3, a conventional optical system for a liquid crystal display device includes a light source 60, an elliptical reflector 61 reflecting a beam emitted from the light source 60, and a light source 60 from the light source 60. Reflects only red as a condensing lens 62 for changing the beam of light in a constant direction, and a dichroic mirror that transmits and reflects the light wavelength of a specific color in the beam output from the condensing lens 62 Blue and Green transmit only the R reflecting mirror 63 for transmitting and only Green among the blue and green transmitted through the R reflecting mirror 63. G reflection mirror 64 which reflects in the same direction as and transmits blue, and B reflection mirror 65 which reflects blue transmitted through the G reflection mirror 64 in the same direction as G. Of the R reflection mirror 63, the G reflection mirror 64, and the B reflection mirror 65; A micro lens 67 for passing the output beam through the corresponding cell of the LCD 66, and a plurality of lenses for the light passing through the micro lens 67 and the LCD 66 to form an image on the screen 68 It consists of (69,70).

The LCD projector configured as described above has light of a color corresponding to different reflection angles by the R, G, and B reflection mirrors 63, 64, and 65 where the light from the light source 60 is installed with the different inclination angles. As shown in detail in FIG. 4, the microlens 67 in charge of the three LCD cells in the horizontal direction can be provided to each of the three LCD cells to receive the incident R, G, and B rays. Since it is possible to form a pixel in a unit capable of expressing one white light, in this case, the light rays starting from the light source 60 are theoretically generated by the R, G, and B reflecting mirrors 63, 64, and 65. Since the image is formed on the screen 68 by penetrating the LCD 66 without any amount being absorbed, it is possible to solve the brightness problem of the screen, which has been raised as a problem in the conventional structure using the color filter. .

Here, the installation state of the micro lens 67 installed in the LCD 66 will be described in detail with reference to FIG. 5. The center of the cell 66-R representing the R of the LCD 66 and the center of the micro lens 67 will be described. In this state, the R, G, and B rays are provided to the three LCD cells in charge of the micro lens 67 in the above-described state, as shown in FIG. 6. R, G, and B rays incident to 67 are provided at different angles in the horizontal direction with respect to the LCD 66, while the R, G, and B rays as described above are provided in the horizontal section of the LCD 66. The angle formed with respect to is incident on the LCD 66 in a state having an angle of '0' as shown in FIG. 7.

On the other hand, the characteristics of the general contrast ratio (maximum transmitted light amount / minimum transmitted light amount: C / R) of the LCD 66 used as described above are shown in FIG. 8, and in general, the contrast ratio is a light beam with respect to the LCD 66. The change is not so severe with respect to the horizontal angle change of, but the change is very severe with respect to the vertical angle change of the light beam. In particular, the viewing angle (angle having the maximum contrast ratio) is usually a predetermined angle (α: about 5 degrees), and the angle with respect to the horizontal cross section of the LCD 66.

Therefore, in the LCD device for a single-panel liquid crystal projector in which the light beams of R, G, and B are provided with the angle of the light beam incident on the horizontal section of the LCD 66 as '0' as described above, the contrast ratio (C). / R) is determined as section A of FIG. 8, which causes a large amount of loss in contrast.

Accordingly, an object of the present invention is to provide an LCD device for a high-brightness single-type liquid crystal projector that is designed to solve the problems as described above and to ensure the maximum contrast ratio of the LCD.

1 is a view showing the configuration of a liquid crystal display device according to the prior art;

2 is a diagram illustrating an example of a color filter used in FIG. 1;

3 is a view showing the configuration of an optical system for a liquid crystal display device which does not use a color filter according to the prior art;

4 and 5 are detailed views showing the LCD and the micro lens of FIG.

FIG. 6 illustrates a state in which one microlens provides R, G, and B rays to three LCD cells, respectively.

7 is a cross-sectional view taken along line BB ′ of FIG. 5;

8 is a graph of the horizontal / vertical angle and contrast ratio of light rays incident on the LCD,

9 is a main configuration diagram of an LCD device for a high brightness single-ended liquid crystal projector according to the present invention;

10 is a cross-sectional view taken along the line CC ′ of FIG. 9.

Explanation of symbols for main parts of the drawings

1: LCD Cell 2: Center of LCD Cell

3: microlens 4: center of microlens

5: LCD60: light source

62: condensing lens 63: R reflection mirror

64: G reflection mirror 65: B reflection mirror

LCD apparatus for a high brightness single-ended liquid crystal projector according to the present invention for achieving the above object is a micro lens installed so that a straight line connecting the center of the micro lens from the center of the LCD cell is inclined by a predetermined angle with respect to the horizontal cross section of the LCD; And a light ray providing means for providing the R, G, and B rays at an angle equal to a straight line connecting the center of the microlens to the horizontal cross section of the LCD.

Hereinafter, exemplary embodiments of the present invention will be described with reference to the accompanying drawings.

9 and 10 show the main parts of an LCD device for a high brightness single-ended liquid crystal projector according to the present invention, which is a straight line connecting the center 4 of the microlens 3 to the center 2 of the LCD cell 1. A microlens 3 is shown which is inclined by a predetermined angle (5 °) with respect to the horizontal cross section of the LCD 5, which microlens 3 extends downward from the center of the LCD cell 1. It is installed with the center moved.

Here, a ray for providing the R, G, and B rays with respect to the horizontal cross section of the LCD 5 at the same angle (5 °) as a straight line connecting the center 4 of the microlens to the center 4 of the LCD cell. The providing means is conventionally the same as its components, but R, G, B from the light source 60 so that the angle of the R, G, B light incident on the micro lens 3 is inclined by 5 ° with respect to the horizontal cross section of the LCD. Since only the component angles up to the reflective mirrors 63, 64, and 65 need to be adjusted, the illustration is omitted. Hereinafter, for the convenience of description, the same reference numerals are used to denote the same components.

Referring to the operation of the present invention configured as described above are as follows.

Light rays generated from the light source 60 are separated into respective R, G, and B rays through the condensing lens 62 and the R, G, and B reflecting mirrors 63, 64, and 65, and the angle of the light is emitted from the LCD 66. 3 LCDs are installed at an angle of 5 ° in the vertical direction with respect to the horizontal cross section of each of the R, G, and B rays, and are installed in the horizontal direction adjacent to each other by the same microlens 3 as in the conventional art. It is supplied at an angle that can be incident on each of the cells 1.

Here, referring to FIG. 8, the LCD has a similar contrast ratio with respect to the incident angle in the horizontal direction, but the maximum contrast ratio is determined at an angle of about the predetermined angle (α = 5 °) with respect to the vertical incident angle. As described above, the R, G, and B rays incident at an angle of 5 ° with respect to the horizontal cross section of the LCD 5 allow the LCD 5 to obtain the maximum contrast ratio.

That is, the relationship between the incident angle of the light beam corresponding to the section B of FIG. 8 and the contrast ratio can be obtained, thereby improving the gray scale represented by the LCD 5 by improving the overall contrast ratio. will be.

As described above, the LCD device for a high brightness single-ended liquid crystal projector according to the present invention can improve the contrast of the LCD by adjusting the angle of the light incident on the LCD appropriately so as to make the best use of the characteristics of the contrast ratio possessed by the LCD. The effect can be obtained.

Claims (1)

A microlens installed so that a straight line connecting the center of the microlens at the center of the LCD cell is inclined by a predetermined angle with respect to the horizontal cross section of the LCD, and a straight line connecting the center of the microlens at the center of the LCD cell with respect to the horizontal cross section of the LCD. LCD device for a high-brightness single-crystal liquid crystal projector, characterized in that consisting of a light ray providing means for providing R, G, B light at the same angle as.